Sluices are a type of dam which allows water to flow through in one direction only. Unlike a simple dam you can control what goes through a sluice as well as control the flow of water. By using an automated sluice system you take away the need to constantly manual open/close gates.

A single layer of sluices placed at the bottom of a wall can be useful in a few ways:

• You can slowly drip water from a large water reserve into a closed area that you want constantly irrigated.
  
• You can use it to quickly flush out bad water during a bad tide into a safe alternative route.
  
• You can prevent water/bad water from flowing into an area you don't want it.

To limit the amount of water being leaked into a closed area you'll need to adjust the downstream depth to less than the fill line of the area you want irrigated. This is an example based on the stream level being 1 level high:

• If the area you're irrigating is blocked by a dam further downstream you'll want to close above downstream depth 0.6.
  
• If the area you're irrigating is blocked further downstream by a leve, terrain, or a closed gate then you'll want to close above downstream depth 0.95.

Placing sluices at the top of a wall allows for a constant flow of water as long as the water level behind it is as high as the sluice.

When built combined with a set of sluices at the bottom of a wall you can fully control the amount of water entering an area that's been blocked further downstream by a dam to ensure your land is constantly irrigated. Water will continue to flow through the top set of sluices as long as water is still flowing. Once a drought takes place and the water level drops behind the top set of sluices then the bottom set will slowly trickle in water as the downstream water level starts to go down.

Bad water mixing in with your drinking water is bad news for beavers. For one they can get sick if they come into contact with bad water, and it will kill everything growing nearby. This is why it's vital for survival that you have a means to separate the good from the bad water and have a means of diverting bad water during a bad tide to a safer location.

A simple set of sluice gates at the bottom of a wall can stop water from being contaminated by bad water and vice versa.

• To prevent bad water from passing through a sluice set close above contamination 5%.
  
• To prevent fresh water passing through a sluice set close below contamination 5%.

Depending on the layout of the land you could set up various sluice gates to ensure only good water enters the area you want your beavers to grow things in and during a bad tide divert the bad water away to the nearest bad water source or have it flow off the map.

In the example to the left the sluices to the left are set to close when contamination is above 5% whilst the sluices to the right are set to close when contamination is below 5%. When a bad tide takes place the bad water will stop flowing to the left and start flowing to the right.

Sometimes you may be required to build gates that aren't in sync with each other. This could be down to too much water being pushed out from the source into a far narrower stream that flooding becomes an issue. By unchecking synchronize with adjacent sluices you can change how different gates behave to ensure a more steady flow.